Corn spirals and method of manufacture

ABSTRACT

Fried snack food product in ribbon-like form, preferably spiral, of a masa dough that has been ground and then further comminuted by cutting to have a maximum particle size of 0.05 inch.

This application is a continuation of application Ser. No. 824,720,filed Jan. 31, 1986, now abandoned.

BACKGROUND OF THE INVENTION

Small snack food products have been manufactured in a wide variety ofshapes and sizes, including scoops, cups, containers, cones, triangles,roll, squares and curls. Corn chips and potato chips are generallyplanar, concave or ridged. Pretzels are long, short, thick or thin, andtwisted into a variety of shapes.

Snack food products have been made from masa in the past, but the masahas been made in a conventional manner by grinding. Grinding istraditional, but produces masa having coarse particle sizes because allattempts to produce very fine particle sizes by grinding generate enoughfrictional heat so that the masa will become overly cooked. This has ledthe public to expect certain mouth-feel and texture characteristics insnack products produced from masa.

Corn has also been processed for use in making snacks on comminutiondevices, such as Fitz mills or hammermills, with a cutting action thatreduce particle size by a cutting action rather than by a grindingaction. Generally, the product of such a process is a masa of reducedcohesion between its particles that results in a characteristicmouth-feel and texture in products made from this kind of material.

Prior art processes for manufacturing corn flour or corn chip snackproducts are also varied. These processes all have at least one grindingstep.

Often the manufacturer of a snack food product will begin themanufacturing process with a prepared flour or meal, which is used toform a dough, masa, or the like. In this case, the manufacturer has noconcern, generally, with the initial material, but contributes to theproduct just the formulation and manufacturing steps that utilize theflour or meal as a raw material. Where the manufacturer does produce theflour or meal, it is generally produced by a grinding, cutting, orattrition step. Since each of these processes requires a different pieceof equipment, generally only one type of operation is performed.

SUMMARY OF THE INVENTION

In its broad aspects, the invention in one embodiment is a cooked snackfood product comprising a ribbon-like piece of fried dough made from amasa that has been ground and then further processed to reduce particlesize by comminution involving a simultaneous grating and cutting action.

According to a preferred embodiment of the invention, this ground,grated and cut masa is extruded through dies that form a ribbon-likesheet. In a preferred embodiment, this sheet is extruded through diesthat also twist it to have a spiral shape. The extruded spiral materialis cut into suitable lengths, which are then fried in hot oil to a finalmoisture content in the range 0.5% to 1.5% by weight. The spiral shapedproduct is marketable and appealing to consumers because of the thinnessof the masa ribbon from which it is manufactured. The thinness of theribbon is dependent upon the reduction of the number of large particlesin the masa. A fine masa provides a more desirable texture in thehelical shaped product due to the second milling step of the process.The second milling step is a comminution of the masa particles bysimultaneous grating and cutting actions. Although the masa produced bythis process may be used to produce a snack food product of any shape,the spiral shape emphasizes the desirable texture for the consumer.

A maximum particle size of 0.06 inch is insured by forcing the masathrough a plate having perforations of the desired maximum size, priorto extruding it.

The preferred snack food structure is a spiral having an axial length ofabout 21/4 inches. The spiral shape gives the product a unique andpleasant mouth-feel in addition to making the spirals particularlyadaptable for use with dips. The gaps between flights trap and hold moredip than a comparably-sized flat ribbon chip, and the twisting of theribbon into spiral form imparts mechanical strength against breakingwhen the spiral passes through dip. The texture of the corn spiral issofter and more delicate than standard corn chips, due primarily to itsprocess of manufacture.

The process of the invention involves subjecting a ground masa tocomminution by simultaneous grating and cutting that reduces the size ofthe particles in the masa. The comminuted masa is then screened toinsure that the maximum particle size cannot exceed 0.06 inch. Thescreened masa is then extruded through a die to a ribbon-like form. Theribbon-like extrudate is then cut to snack-sized pieces of the desiredlength, which in turn are cooked in hot oil to achieve a final productmoisture content in the range 0.5% to 1.5% by weight.

When beginning the process with whole corn kernels, the process ofmanufacturing involves adding water and lime to whole kernels of cornand cooking the mixture at the boiling point. Cold water is added to themixture and the mixture is allowed to stand for approximately eighthours. The kernels are then washed with additional water to remove thehulls, after which the kernels are ground between rotating surfaces toform masa.

Masa is a sticky, pliable paste that consists of an agglomeration ofmoist, soft particles of different sizes. The masa is then comminuted inan Urschel Comitrol mill or like device that has a simultaneous gratingand cutting action. This creates a very fine masa with particles whichwill not block the narrow openings of the extruder dies necessary toproduce the helical shape. The finely ground masa is then passed throughextruder and helix-forming dies. The resulting corn spirals are extrudeddownward into a continuous fryer. After frying, the corn spirals may beseasoned or flavored, then cooled and packaged.

DETAILED DESCRIPTION OF THE INVENTION

In one preferred embodiment, the snack food product of the invention isa fried and seasoned corn dough product formed in a spiral shape. Thecolor of the product is a golden yellow, and the flavor of the saltedproduct is that of toasted corn. Other seasonings or flavors that may beapplied to the corn spiral to give it more distinctive tastes are nachoflavoring, barbeque flavoring, or butter flavoring.

The soft and delicate texture of these corn spirals, as well as theircrunch, is primarily due to the process of manufacture, and also to theoil and moisture content of the product. The oil content of these cornspirals is within the range of 28.0% to 36.0%, with an optimumpercentage of 34.0%, while the residual moisture content is within therange of 0.5% to 1.5%, with an optimum value of 1.0%.

The process of manufacturing a preferred snack food product with thesecharacteristics begins by delivering whole-kernel corn from its storagesilo to a steam-jacketed cooking kettle by means of a screw conveyor.Approximately 450 pounds of corn form a batch of convenient size. Thepreferred type of corn is a pale yellow Hybrid Variety or a 1:1 blend ofwhite and yellow varieties.

After the corn has been delivered to the kettle, 80 gallons of water aremetered into the kettle and the temperature of the corn and watermixture is brought to about 150° F. At this point, 3 pounds, 11 ouncesof lime (calcium hydroxide USP or its equivalent) are added to the cornand water mixture, and the entire mixture is cooked for 15-35 minutesafter reaching the boiling point at atmospheric pressure. The steampressure applied to the kettle jacket during the cooking stage is about60 psig. The cooking time may be varied within the limits given, asrequired, in order to obtain the desired oil absorption in the finishedproduct.

When the cooking stage is completed, the cooked corn is discharged intoa transfer tank. An additional 70 gallons of cold water are added to themixture by rinsing the cooking kettle into the transfer tank. Then theentire corn/water mixture is pumped into rectangular, stainless steel,open-top soaking tanks of approximately 240 gallons capacity. The cornis levelled in the soaking tanks so as to be completely covered withwater, and then allowed to soak quiescently for preferably 8 hours and15 minutes (although the corn may soak longer, for a maximum time of 12hours and 15 minutes).

When the soaking is completed, each batch is pumped into a rotary washerwhere the corn is washed by spraying with fresh water. The washingremoves corn hulls and other debris, as well as any residual lime. Thehulls are considerably softened from the previous heat and limetreatment stage. The washings are discarded to waste or are taken forby-product recovery.

The washed and drained dehulled corn is then transferred to mechanicalgrinders, where it is ground into masa. The mechanical grinders operateto grind the corn between rotating grinding surfaces. The coarseness ofthe ground masa is controlled by visual examination, and by adjustmentof the grinding surfaces. A conveyor belt transports the ground masa toan Urshel Comitrol mill fitted with a #30 grinding head. A Teflon-linedfunnel is located on the top of the Comitrol mill, the point at whichthe masa enters. The Teflon surface of the funnel keeps the masa fromsticking to the inside surface of the funnel. In addition, the entireinside surface of the Comitrol mill, except for the lid, the impeller,and the grinding head, is also lined with Teflon.

An oil spray system is mounted above the entrance funnel and sprayscottonseed oil onto the masa as it enters the Comitrol mill to becomminuted. The spray rate is about one gallon of oil per hour ofgrinding time. The oil acts as a lubricant to keep the masa fromsticking to the inside of the mill, and also contributes to the texturecharacteristics of the finished product.

Also necessary to insure the delicate texture characteristics of thecorn spirals product is the comminuting step performed by the Comitrolmill. The mill reduces the size of particles by simultaneous grating andcutting, rather than grinding. A mechanical grinder alone could notgrind particles as fine as those comminuted by the Comitrol mill withoutcreating much frictional heat and consequently turning out an extremelyovercooked masa. Comminution through the Comitrol mill only, withoutpregrinding, produces a masa of reduced cohesion between its particles,which gives a very different and less desirable texture to the finalfried product.

The Comitrol mill has a rotary impeller that is disposed within aperforated cylindrical "cutting head". Material that is fed into thebore of the cutting head is forced by the impeller against the innersurface of the cutting head and the material is forced by the impellerthrough the rectangular perforations in the cutting head. The portionsof the cutting head about the perforations are sharpened, so that agrating, as well as a cutting action, is applied to masa that is forcedthrough the perforations by the impeller. Perforation sizes aregenerally uniform in a given cutting head, but different cutting headshave perforations of different dimensions. The dimensions of therectangular perforations in the preferred #30 cutting head are 0.030inch by 0.160 inch.

In addition to enhancing the texture of corn spirals, the comminutingstep further reduces the size of particles in the masa which otherwisewould have been too large to pass through the openings of the extruderdies after only the one grinding step. After having its particle sizereduced by the simultaneous grating and cutting action of the Comitrolmill, the masa is discharged from the bottom of the Comitrol mill onto aconveyor belt that transfers the masa to another conveyor belt, whichdelivers the masa to a supply hopper located on top of a Marlinecontinuous-type extruder or the equivalent. The moisture content of themasa at this point is about 45% to 54%.

The Marlin extruder is a piston-type extruder that is fitted with aspecial flared barrel or "bell". The flared barrel is modified tocontain a changeable screen which prevents any large particles fromgetting into the dies and blocking them. The preferred screen is made of22-gauge stainless steel, and is perforated with holes that are 3/64thsinch (about 0.05 inch) in diameter. The holes are staggered, and thereare about 131 holes per square inch. Screens with holes of differentsizes may be used. Generally, the size of the holes of the screen is thesame as the size of the opening of the die being used, so as to preventparticles that are too large to pass through the die opening fromreaching said opening. If the screen becomes blocked, it should beremoved and replaced with another screen by means of a fast-actingscreen-changing mechanism. The screen acts as a "fail-safe" to removeany remaining large particles of masa which might otherwise havesurvived the Comitrol mill treatment and which would severely block theextruder dies. Even a slight or partial blockage of a die would createsevere shape distortion of the resulting corn spiral, resulting in aless desirable product for the consumer. The comminuting step producesmasa with particles which will not cause rapid blockage of the screen orthe extruder dies. Masa subjected to only the grinding step completelyblocks the screen in a short time and thereby blocks flow of the masa tothe extruder dies. A masa that is the product of a single grinding stepleaves 0.2134%, on a dry weight basis, on the preferred screen of theinventive process, in contrast to 0.0127%, on a dry weight basis, thatremains on the screen after a masa that has been both ground andcomminuted by a Comitrol mill is passed through the screen. Thedifference in the amount of masa left on the screen accounts for therapid blockage of the screen that occurs with a ground masa, and thereduced blockage that occurs with a masa that has been both ground andcomminuted by a Comitrol mill.

The masa is forced by pressure through an elbow-shaped extruder head,and thence through a spiral-forming die into 26 discrete, twistedribbons which form spirals that are between 0.20 inch and 1.0 inch, andpreferably 0.515 inch, in diameter. The thickness of the ribbon ispreferably in the range of about 0.055 inch to 0.065 inch. Thicknessesas great as about 0.100 inch can be useful, but thinner products arepreferred. Spiral shaped products have greater resistance to breakage.Each of the spirals preferably has two flights in 21/4" of length.However, the gap between flights can range from 0.10 inch to 2.0 inches.The spirals are automatically cut into lengths of about two inches or21/4 inches by a cutting wire as they emerge from the extruder head.

Each spiral as extruded resembles a spiral chute except that the spiralis not wound on a cylinder but rather is just twisted on itself about anaxis. The outer edge of each spiral, if extruded in a perfectly spiralshape, would define a helix.

The cut masa spirals fall directly into a fryer containing vegetablecooking oil maintained at a temperature of 400°-405° F. (204°-207° C.).Mechanical action of the fryer moves the spirals through the fryer foran average residence time of about one minute, 45 seconds. The length oftime is adjustable, however, to correspond with the completion of thefrying of the spirals. Completion of fraying corresponds with cessationof bubbling and a residual moisture content in the spirals of 1.5% orless. The free fatty acid level of the oil in the fryer (a measure ofbreakdown of the oil) is maintained at a maximum of 0.40%.

When the corn spirals exit the fryer, they pass through a tumbler wheresalt is applied at a level equivalent to 1.30% of the finished product.At this point, seasonings or flavorings such as nacho-cheese, barbequeor butter flavorings may also be applied to the corn spirals.

The seasoned product is then transported to the packaging area onconveyors. Cooling of the product occurs during this period. The productis finally packaged by automatic packaging machinery, and cartoned.

The foregoing process description is concerned with the production of acorn-based snack food product in spiral form. This represents apreferred embodiment of the invention. While one might expect the friedcorn spirals snack food product to be essentially uniform in size andshape, in fact the extrusion process is not perfect, and the drop of theuncooked spirals from the outlet of the extrusion die to the surface ofthe hot cooking oil results in an impact. This impact may cause shapedistortions of various kinds, so that the spirals are not uniform.Similarly, during transport through the cooking oil, the application ofheat often causes some distortion, and jostling with other spirals inthe fryer may also cause changes in shape. Accordingly, the packagedspiral products may not be perfect helices. Good spirals are consideredto be generally straight, and anything up to a 45° deviation from axialis considered essentially straight. Usually about 50% maximum of thespirals are straight as so defined. When the bend is more than 45° fromaxial, the spirals may be good products in shape. Generally not morethan 20% of the spirals snack food product are bent more than 45° fromaxial. The remaining products will have other degrees of distortion, andgenerally up to about 10% of the spiral product will be shorter than oneinch, despite the fact that the production process sought to producespiral products of about two inches in length.

To make a nacho cheese-flavored corn spiral product, a nacho cheeseseasoning is dusted onto the surface of the fried product in an amountof about 7% by weight of the finished fried product, while still hotfrom the fryer. Products having other flavors may be produced in similarfashion.

While the preferred snack food product is a corn spiral fried productproduced by the process described in detail above, other snack foodproducts may be produced that have similar taste, mouth-feel andtexture, but not necessarily the spiral shape. Thus, the dies may beselected to produce an essentially straight ribbon that is cut into thedesired lengths. Such straight ribbon-like products come out of thefrying operation having less than straight shapes, of course, because ofthe happenings described with respect to the corn spirals that distortthem. Similarly, other dies can be used to produce straight ribbon-likeproducts with a slight twist. Also, by using suitable manufacturingtechnique, snack food products shaped like cups, scoops, cones, rolls,and curls, for example, can be produced. In addition, other cookingtechniques such as baking may be used instead of frying.

The helix-forming dies that are used in the production of the preferredspiral snack food embodiment of the invention are simply thosehelix-forming dies that have traditionally been used by the pastaindustry to make a spiral pasta product called either "rotini" or"spiralli". Other dies are readily available to make ribbon-shapedproducts of different shapes, or to form extruded straight ribbons intoother shapes.

In addition to ribbon forms, the masa of the invention is generallyuseful in producing cooked snack products in a variety of shaped forms.Thickness is a problem as to obtaining uniform cooking, but this can behandled in a variety of ways, as by microwave cooking, or by acombination of frying with microwave cooking, or by using hollow shapes.

While the invention has been disclosed by reference to the details ofpreferred embodiments, this disclosure is intended in an illustrativerather than in a limiting sense, as it is contemplated thatmodifications will readily occur to those skilled in the art, within thespirit of the invention and the scope of the appended claims.

What is claimed is:
 1. A process for producing a cooked snack foodproduct comprising subjecting a ground masa made from dehulled cornkernels to comminution by simultaneously grating and cutting thatreduces the size of particles in the masa, passing the comminuted masathrough a die to a ribbon-like form, severing said ribbon-like materialto form snack-sized pieces, and cooking said pieces.
 2. The process ofclaim 1 further comprising screening the masa prior to extrusion suchthat said masa contains particles having a maximum size which does notexceed the largest dimension of the die opening.
 3. The process of claim1 wherein cooking said pieces comprises frying in hot oil to a finalmoisture content in the range 0.5% to 1.5% by weight.
 4. The process ofclaim 1 wherein the die forms a ribbon-like extrudate having a spiralshape.
 5. The process of claim 4 wherein adjacent windings of saidspiral shape are separated by gaps of at least 0.10" but not in excessof 2.0", measured axially, and said severed pieces retain their shapes.6. The process of claim 5 wherein cooking said spiral pieces comprisesfrying in hot oil to a final moisture content in the range 0.5% to 1.5%by weight.
 7. The product produced by the process of claim
 1. 8. Aprocess for producing a snack food product comprising the sequentialsteps of:(a) boiling corn kernels in a water and lime solution andallowing the mixture to stand; (c) washing the corn kernels with waterto remove the hulls; (d) grinding the dehulled corn between rotatinggrinding surfaces to form masa; (e) comminuting the particles in themasa by a simultaneous grating and cutting action to reduce particlesize; (f) delivering the ground, comminuted masa into a piston-typeextruder which applies pressure on the masa to force said masa throughan extruder head and through helix-forming dies that form a helicalribbon of extruded masa, (g) cutting the extruded masa as it passes fromthe die, and (h) allowing said masa to drop into a fryer to cook it. 9.The process of claim 8, wherein said extruder head has a screen ofperforated metal through which the masa must pass before reaching thedie.
 10. The process of claim 9, wherein the screen passes onlyparticles having diameters less than about 0.05 inch.
 11. The productproduced by the process of claim 8.